Pump or motor



Jm 1940- F. BURGHAUSER 2,138,702

PUMP 0R MOTOR Filed Sept. 9, 1937 2 Sheets-Sheet 1 Jan 30, 1940. BURGHAUSER 2,188,702

PUMP 0R MOTOR Filed Sept. 9, 1937 2 Sheets-Sheet 2 Patented Jan. 30, 1940 2,188,? 02

UNITED STATES PATENT OFFICE PUMP R. MOTOR Franz Burghauser, Nuremberg, Germany Application September 9, 1937, Serial No. 163,141 In Germany August 13, 1937 4 Claims. (01. 103-128) This invention relates to pumps or motors and ther diagram similar to Fig. 3 showing the threads more particularly to pumps or motors provided of the side-spindle together with the bores formwith screw-spindles. ing part of the construction of Fig. 1, Fig. 5 is My invention has for its general object to dea vertical view of a side-spindle constructed with vise a construction of such screw-pumps or screwbores which are modified with respect to the bores 5 motors, in which the forces acting on the screwshown in Fig, 1, Fig. 6 is a further diagram showspindl-es are properly counteracted and equalized ing said spindle of Fig. 5 developed out in a plane, to prevent any undue strains from being im- Fig. 7 is a modified construction of a screwposed upon the spindles. pump with a single spindle in which the afore- 10 By action of the pressure of the operating liqsaid transverse forces acting on the spindle uid forces are exerted in axial direction upon the are counteracted by providing special bores in spindles of screw-pumps or screw-motors, these the pump-casing, and Fig. 8 is a central longiforces heretofore having been generally equalized tudinal section through a further modified conby a counter-pressure exerted upon surfaces postruction of my present pump having also a sinsitioned perpendicularly to the axis of said spingle spindle, wherein the transverse forces are 5 dles. For instance, in order to attain this, the counteracted by providing special channels withspindles of such pumps or motors have been in the bearings. PI'OVidBd With axial bores Special equa In the construction of my present pump shown pistons have been used for this purpose. in Fig. 1 the transverse forces acting upon the Besides the forces arising in axial direction, main spindle a are practically of no importance, m

however, there will also be exerted forces upo while heavy strains are imposed upon the sidethe spindles by action of the pressure of the spindle b. In the diagram of Fig. 3 which repreo-perating liquid, these forces being tra erse y sents the outer periphery of the side-spindle, directed with respect to the axes of said spinthe whole of the operating pressure in the posidles as disclosed herein for the first time. These tion of the two spindles shown in Fig. 1 acts 25 transverse forces, which as a rule are even in along the heavily shaded surfaces in radial direcexcess to the axial forces, had heretofore been tion upon the side-spindle, while along the lighttrensmitted p the bearings and y Way o the 1y shade-d surfaces there is exerted only one-half threads of the spindles upon the pump-casing. of the operating pressure. Within the gap be- However, the friction produced by these forces tween the thread I and the pump-casing there is of such an excessive amount, that screw-motors prevails a pressure, the so-called gap-pressure, frequently will not be able to start, this being which at this place is equal to the full operating due to the fact that the frictional moment to pressure and acts in radial direction upon the be overcome is larger than the torque exerted thread I. Onto the surfaces of the groove interupon h spindles by he pr sure f the operatmediate said threads I and II the full operating 35 ing liquid. pressure does not act over the entire width of In order to more fully explain my present insaid groove, but only over a reduced width in vention I will first illustrate herein by way of accordance with the reduced diameter. Upon an example how these transverse forces acting said thread II a pressure acts only over one-half upon the screw-spindles are produced by the of the width of said thread in accordance with 40 pressure of the operating liquid. This action of the full operating pressure acting upon the upper the transverse forces, as far as I am aware, has edge of th thr d and ith th pressure in the heretofore never been described nor even mengroove positioned below said thread II, this pre tioned. As an example I have chosen a screwsure being assumed to be zero in the present case.

pump having a main spindle with a single thread Apparently a considerable surplus of radial strain 45 and a side-spindle with a double thread. will be imposed upon the visible half of the side- In the drawings, Fig. 1 is a longitudinal censpindle with a projected component P. tral section thro h y novel -pump com- According to my invention the gap-pressures p s an arrangement hereby S d axial fOrceS intermediate the rotating spindle-surfaces x and 0 may successfully be counteracted by providing the pump-casing are regulated and disposed of bores within the threads of said side-spindle, in such a manner that the transverse forces act- Fig. 2 is a top-view of the spindles forming part ing upon the spindles will either be in part counof the construction of Fig. 1, Fig. 3 is a diagram teracted or wholly disappear or even act advanshowing the threads of said main and said sidetageously in reversed direction.

spindle developed out in a plane, Fig. 4 is a fur- A partial equalization of the transverse forces nu..- I

may be attained, if the threads of the spindles are provided with transverse bores m as shown in Figs. 1 and 2 as well as in the diagram of Fig. 4. As may easily be seen, the front visible half of the spindles may thus be relieved from the gap-pressure, while this pressure acts upon the rear part of the spindles. In like manner the spindles are also provided with bores at their ends.

adjacent the entrance of the operating liquid, because upon further rotation of said spindle there will likewise arise gap-pressures at this place which must be counteracted.

While the aforedescribed arrangement is designed to relieve the spindle of transverse forces arising from thread to thread, it is also possible to attain such relief by transverse bores from groove to thread. As an example of this, there may again serve the above-mentioned pump having a main spindle with a single thread and a sidespindle with two threads. In Fig. 5 I have shown only the side-spindle n which is to be relieved of strain, while Fig. 6 shows diagrammatically the forces acting upon said spindle. In this case bores lead from the ends of the threads to the opposite grooves, said bores being designated by 0, 0 and p, p in Fig. 6.

Thus the thread I will be relieved from strain at the point 0, while the thread II is under action of the full pressure of the operating liquid. In order to render these equalizing surfaces as effective as possible, the bores o, p are enlarged to merge into a depressed surface at the exit end, which surface may even extend beyond the spindle as indicated in dashdotted lines in Fig. 6.

While the so far described possibilities of providing a relief of transverse forces consist in the provision of transverse bores in the spindles, such bores may also be provided in the stationary part of the pump, that is in the pump-casing, in which case the gap-pressures arising intermediate the threads and the casing are controlled by the threads of the spindle as shown in Fig. '7. The transverse bores q-q, 7-4, and s-s', which are provided as shown in Fig. 7 in the pump-casing are in connection with each other in pairs and thus will act to relieve one side of the spindle from pressure while the other side thereof is under the pressure of the operating liquid.

Finally, according to my invention, there is the possibility to regulate the gap-pressures between gap-surfaces which are positioned outside of the pump-casing as indicated in Fig. 8. According to Fig. 8 oil under pressure is passed from the pressure-space it through the cylindrical gap of the bearing 11 and through a longitudinal bore in the casing and returned into the suction-space. On the one side the bearing is relieved from pressure by a bore 10 leading to the suction-space, while the other side is under the pump-pressure directly from the pressure-space, through a bore a:. In accordance with this, also the bearing in the suction-space is properly constructed to counteract that part of the transverse thrust exerted'onto said suction-space. In this construction the proper dimensioning of the diameters of the bearings is connected with the further advantage that together with known means the axial thrust arising will be counteracted. In addition to this, there may also be provided the aforedescribed means which serve to equalize transverse forces.

The aforedescribed means for counteracting the transverse forces acting upon the spindles as well as the combination of such means with an arrangement providing for relieving the spindles from strain in axial direction may principally be employed in connection with all spindles forming part of various kinds of screw-pumps and screwmotors and will always be effected in proportion with the pressure of the operating liquid.

My invention, accordingly, provides the possibility of constructing screw-pumps or screw-motors which are fully relieved from forces acting between operating parts and the operating characteristics of the materials employed do not need to comply with special requirements. Therefore, by my invention, it will be possible toconstruct screw-pumps or screw-motors from cheap structural materials and to attain an almost unlimited lifetime of the pump or motor.

I claim:

1. In a pump or motor comp-rising a plurality of interengaging screw spindles the convolutions of the threads of said spindles describing at least one complete turn about their respective axes, a casing housing said screw spindles with a running fit with the addenda of said spindles, and means comprising a by-pass connecting the area between the immediately adjacent surfaces of the addendum of at least one of said spindles and said housing with the opposite side of said spindle for equalizing the pressures on opposite sides of said spindles, whereby the forces exerted on the spindles by the pressure of operating fluid between said adjacent surfaces transverse to the axes of said spindles, are counteracted.

2. In a pump or motor, the combination of a. plurality of interengaging screw spindles, the convolutions of the threads of said spindles describing at least one complete turn about their respective axes, a housing substantially encompassing said screw spindles with a running fit with the addendum of said screw spindles, and means comprising a transverse bore extending through at least one of said spindles between substantially opposite radial extremities thereof and connecting the area between the immediately adjacent surfaces of the addendum of said last named spindle and said housing on one side of said spindle, with the corresponding area on the opposite side of said spindle, for equalizing the pressures on opposite sides of said screw spindle, whereby the forces exerted on the spindle by the pressure of operating fluid between said adjacent surfaces transverse to the axis of said spindle, are counteracted.

3. In a pump or motor, the combination of a plurality of interengaging screw spindles, the convolutions of the threads of said spindles describing at least one complete turnabout their respective axes, a housing substantially encompassing said screw spindles with a running fit with the addendum of said screw spindles, and means comprising a plurality of transverse bores extending through at least one of said spindles between substantially opposite radial extremities thereof and connecting'the areas between the immediately adjacent surfaces of the addendum of said last named spindle and said housing at spaced points on one side of said spindle, with corresponding areas on the opposite side of said spindle, for equalizing the pressures on opposite sides of said screw spindle, whereby the forces exerted on the spindle by the pressure of operating fluid between said adjacent surfaces transverse to the axis of said spindle, are counteracted.

4. In a pump or motor, the combination of a ing said screw spindles with a running fit with the addendum of said screw spindles, and means comprising a transverse bore extending through. at least one of said spindles from the addendum of said spindle on one side to the space between the addenda on the opposite side of said spindle, connecting the area between the immediately adjacent surfaces of the addendum of said spindle and said housing on one side of said spindle, with the opposite side of said spindle, for equalizing the pressures on opposite sides of said screw spindles, whereby the forces exerted on the spindle by the pressure of operating fluid between said adjacent surfaces transverse to the axis of said spindle, are counteracted.

FRANZ BURGHAUSER. 

